Porifera and Cnidarians Lab

Phylum Porifera - The sponges

Scypha -cross section

Radial Symmetry

Body Shape: Cylindrical

Asexual and Sexual Reproduction

Phylum: Porifera

Class: Calcarea (=Calcispongiae)

Scypha (=Grantia) sp.

Spicules - note the single - and 3-rayed calcareous spicules

Skeleton: Composed of needle-like calcium carbonate spicules (calcite)

Body Plan: Exhibits a Syconoid canal system.

Euplectella aspergillum - Venus' Flower Basket

Observe: section of skeleton, you can move the section and/or change magnification if you want to

Phylum Cnidaria

Class Hydrozoa

Hydra sp. - model

Cnidocytes containing nematocysts (stinging organelles), triggered by a hair-like cnidocil.

Phylum: Cnidaria

Class: Hydrozoa

Hydra sp.

Female Cross Section

Observe ovaries that appear as distinct tissues between the mesoglea and the epidermis

Phylum: Cnidaria

Class: Hydrozoa

Hydra sp.

Male Cross Section

Observe: Testes (Distinct regions in epidermis)

Phylum: Cnidaria

Class: Hydrozoa

Obelia sp. - a colonial hydroid

Exhibits alternation of generations (metagenesis), cycling between a sessile benthic polyp colony and a free-swimming sexual medusa stage.

Phylum: Cnidaria

Class: Hydrozoa

Physalia physalia

Portuguese man-of-war: a floating marine colony made of specialized individual animals that drift together on the ocean surface

Phylum: Cnidaria

Class: Scyphozoa

Aurelia sp.

Planula Larva

The planula larva of the moon jellyfish (Aurelia) is a tiny, oval, and ciliated free-swimming stage that forms shortly after fertilization in the life cycle of true jellyfish in the class Scyphozoa

Phylum: Cnidaria

Class: Scyphozoa

Aurelia sp.

Observe: scyphistoma larva (polyp stage)

oral tentacles

body tube

basal disc

Reproductive stage: Asexual

Next stage in life cycle: Ephyra

Phylum: Cnidaria

Class: Scyphozoa

Aurelia sp.

Observe: Strobila Larva

A critical asexual reproductive stage where a polyp transforms to produce young motile medusae

Phylum: Cnidaria

Class: Scyphozoa

Aurelia sp. - young medusa

A tiny, free-swimming larval jellyfish released during the asexual strobilation phase of a benthic polyp

Phylum: Cnidaria

Class: Scyphozoa

Aurelia sp. - Moon jellyfish

Preserved specimen

displays a translucent, saucer-shaped bell and four characteristic horseshoe-shaped gonads

Phylum: Cnidaria

Class: Anthozoa

Collection (museum box) of horny and stony corals

Exclusive marine organisms that exist solely as sessile polyps, lacking any free-swimming medusa stage in their life cycle

Exhibits only the polyp stage, reproducing sexually via broadcast spawning or brooding, and asexually through budding or fragmentation.

What is the basic difference between Horny Corals and Stony Corals?

Stony corals: build hard calcium carbonate skeletons

Horny corals: build flexible skeletons made of a protein called gorgonin, often reinforced with microscopic bone-like structures called sclerites.

Phylum: Cnidaria

Class: Anthozoa

Stony Corals - Various types

Observe: Various types of calcareous exoskeletal structures secreted by different species of corals cups or sockets in which animals are located.

Habitat: shallow, warm, tropical marine waters

Scypha sp. longitudinal section

Cuts vertically down the length of its vase-like body.

This perspective reveals a syconoid canal system structured to pump water and trap food.

Leucosoloenia sp. whole mount

An entire, intact specimen of the simple marine tube sponge

Spongin Skeleton

Fibrous protein similar to collagen that forms the flexible internal skeleton of many sea sponges

Phylum: Porifera

Spongilla sp. - gemmules

Internal survival pods that allow freshwater sponges to stay alive through harsh conditions like freezing cold or dry drought

Hydra oligactis - whole mount

Brown hydra

The entire intact structure of this tiny freshwater polyp

Hydra oligactis

Brown hydra - cross-section turtox

Highlights the classic diploblastic body plan of a cnidarian polyp.

Under a microscope, this section looks like a ring or donut of cells surrounding a central hollow space

Live hydra

A tiny, predatory freshwater animal related to jellyfish that can regenerate its entire body and shows no natural signs of aging

Habitat: Freshwater, slow-moving streams

Obelia

Class: Hydrozoa

Phylum: Cnidaria

Asexual Reproduction (polyp form)